Cu 2 S Wires With Controllable Thickness on Li Foil for Stable and High‐Performance Lithium Metal Anodes

ABSTRACT Lithium (Li) metal is an attractive anode for next‐generation high‐energy‐density batteries. However, its practical implementation is limited by interfacial instability and dendritic growth, often accompanied by high interfacial resistance. In this study, a strategy combining electrodeposition with a mechanical rolling process is presented to lower the interfacial resistance and suppress Li dendrite growth. By adjusting the current density, the thickness of Cu 2 S wires is controlled at a fixed synthesis duration. A Cu foil bearing 0.32 µm thick Cu 2 S wires is rolled with a Li foil, transferring the wires onto the Li surface to form Li@Cu 2 S wire. During rolling, spontaneous lithiation generates a Li 2 S‐rich solid electrolyte interphase embedded with three‐dimensional Cu dots. Li@Cu 2 S wire symmetric cells exhibit stable Li plating/stripping for >3500 h at 1 mA cm −2 and 1 mAh cm −2 . Moreover, Li@Cu 2 S wire∥LiFePO 4 full cells retain more than 95% of the initial capacity for over 450 cycles at 1 C, demonstrating outstanding electrochemical performance. This work provides a simple and effective approach to enhancing Li anode performance through interfacial engineering.